Certificates “can deliver greater income returns than associate and even some bachelor’s degrees,” the report said.

That’s especially true for certificates in health-care fields, such as licensed practical nurse or pharmacy technician, which make up 43 percent of the total awarded. Certificates in technology, construction trades, and mechanic and repair trades also raise earnings.

For many students, “completing a certificate can be the most direct path to college completion and career success,” the report concludes.

Completion rates are two to three times higher for students in certificate programs, says the study’s author, Brian Bosworth of FutureWorks. Students are motivated by the immediate job pay-off and it’s easier for students to complete a one-year program. Furthermore, certificate students may be able to start training immediately, while would-be transfer students are placed in remedial classes.

Community colleges are increasing the number of short-term certificates, which help experienced workers update their skills but have no labor-market payoff for people trying to start a new career. Community colleges are offering fewer long-term (one year or more) certificates.

By contrast, the for-profit sector is offering more long-term certificates. Many career colleges offer well-designed certificate programs with a strong link to the job market, Bosworth said.

The report calls for doubling and then redoubling the number of certificates awarded over the next 10 years. It also suggests community colleges should develop more long-term certificates and offer fewer short-term programs. Students should have the option of earning certificates on the path to an associate degree, the report added.

President Obama’s college-completion goal — making the U.S. first in the world in college attainment — includes at least one year of postsecondary education for every American. Certificate completion should count toward colleges’ attainment goals, the report says. However, “states and institutions must ensure that certificate programs are of high quality, rigorous enough to have real value, tailored to the job market, widely available, and designed for timely completion.”

There’s tremendous variation in the number of certificates awarded in each state. Arizona is the leader, Bosworth says. “It has by far the highest percentage of 25- to 49-year-olds in postsecondary education. They aggressively reach out to adults and their community colleges are remarkably accessible.” In Connecticut, only 12 people completed a long-term certificate last year.